The present invention relates to a method and to a device for the optimizing of the performance characteristics of a liquid crystal display matrix screen as a function of the angle of observation.
One problem that is often encountered by the users of liquid crystal display (LCD) screens, using especially those using twisted nematic liquid crystals, is the deterioration of the legibility of the images displayed when the observer moves away from an axis of observation normal to the screen.
This deterioration is characterized by a fall in contrast and a colorimetrical drift (entailing a desaturation or reversal of the colors).
This phenomenon is chiefly related to the fact that an LCD screen possesses a limited field of observation.
This field of observation is even further reduced when images containing shades of gray are displayed, as is the case for example in synthetic imaging. This effect necessitates an anti-aliasing type of processing operation to improve image quality.
In the prior art, this lowering of the performance characteristics is compensated for by a overall adjustment of the voltages used to address the liquid crystal display screen. This is done by means of a control potentiometer placed in the vicinity of the screen.
An object of the invention is a method by which optimum legibility of the images shown on a liquid crystal display screen can be obtained automatically, whatever may be the observer's position with respect to the screen, hence whatever may be the direction of observation. An object of the invention is also a device for the implementation of this method.